Dual layer solid state batteries

ABSTRACT

Methods for fabrication of electronic systems and systems therefrom are provided. An electronic system includes a first substrate ( 202 ) having a first surface ( 202   a ) and a second substrate ( 208 ) having a second surface ( 208   a ) facing the first surface. The system also includes a plurality of battery cell layers ( 106 - 112 ) disposed on a plurality of laterally spaced areas on the first and second surfaces ( 203, 209 ). In the system, portions of the battery cell layers on the first surface are in physical contact with portions of the battery cell layers on the second surface and the battery cell layers on the first surface and the second surface form a plurality of electrically interconnected battery cells ( 206, 212 ) on the first and the second surfaces that are laterally spaced apart and that define one or more batteries ( 200 ).

FIELD OF THE INVENTION

The present invention relates to devices including batteries and methodsfor forming the same, and more specifically to devices including duallayer solid state batteries and methods for forming the same.

BACKGROUND

Micro-Electro-Mechanical Systems (MEMS) typically integrate electronicand mechanical elements, sensors, actuators, and the like on a siliconsubstrate utilizing micro-fabrication technology. The fabrication andintegration of these elements on a single substrate makes possible therealization of complete systems on a chip. However, MEMS radio frequencyand optical relays commonly use electrostatic actuators requiring 80 to120 volts DC for operation. Consequently, exploitation of the MEMStechnologies has generally been limited by the availability ofinexpensive, compact sources of energy.

In larger consumer electronic devices, such as notebook computers andcameras, batteries are typically formed by connecting multipleindividually packaged cells in series in order to create batteries withmore power and higher voltages. Another approach to creating a highvoltage battery is to form cathode and anode electrode layers onopposite sides of an impervious conductive foil and then stack thebipolar sheets with intervening ionically conductive electrolyteseparators one upon the other. The resulting so called bipolar batteryeffectively connects each pair of electrodes in series thereby forming ahigh voltage without requiring a significantly larger amount of space.Such bipolar batteries are difficult to manufacture and are generallynot in prevalent use. Moreover, current battery-on-semiconductortechnologies generally do not permit the formation of such multi-layerbipolar batteries. For example in the case of lithium thin filmbatteries in MEMS, anode materials generally cannot be subjected to theanneal temperatures required for cathode materials. Accordingly, thefabrication of anode and cathode on a common conductive substrate is notfeasible and such battery structures are generally limited to a singlebattery cell layer produced by sequentially fabricating the cathode, theionically conductive electrolyte separator and then the anodeindividually. As a result, a significant area of a MEMS substrate mustbe set aside to form a large number of single layer batteries to providesufficiently high voltages for the device. This limits the minimum sizepossible for some types of integrated batteries. Accordingly, theminimum size possible for MEMS devices including such batteries is alsoeffectively limited.

SUMMARY

Embodiments of the present invention concern methods for fabrication ofdual layer solid state batteries and devices therefrom. In a firstembodiment of the invention, an electronic system is provided. Thesystem includes a first substrate having a first surface and a secondsubstrate having a second surface facing the first surface. The systemfurther includes a plurality of battery cell layers disposed on aplurality of laterally spaced areas on the first and second surfaces. Inthe system, the portions of the battery cell layers on the first surfaceare in physical contact with portions of the battery cell layers on thesecond surface. The battery cell layers on the first surface and thesecond surface form a plurality of electrically interconnected batterycells on the first and the second surfaces that are laterally spacedapart and that define one or more batteries.

In a second embodiment of the invention, a method for forming anelectronic system is provided. The method includes providing a firstsubstrate having a first surface and a second substrate having a secondsurface. The method also includes forming disposing a plurality ofbattery cell layers on respective plurality of laterally spaced areas onsaid first and second surfaces. The method further includes aligning thefirst and the second substrates so that portions of the battery celllayers on the first surface are in physical contact with portions of thebattery cell layers on the second surface, where the battery cell layerson the first surface and the second surface form a plurality ofelectrically interconnected battery cells on the first and the secondsurfaces that are laterally spaced apart and that define one or morebatteries.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of a portion of a battery substrate,including a battery bank in accordance with an embodiment of theinvention.

FIGS. 2A and 2B are exploded and assembled views of a a battery inaccordance with an embodiment of the invention.

FIGS. 3A and 3B are exploded and assembled views of a system including abattery in accordance with an embodiment of the invention.

FIG. 4 shows an assembled view of a system including battery and analternate configuration of power connections in accordance with anembodiment of the invention.

FIG. 5 shows an assembled view of a stacked system including a batteryin accordance with an embodiment of the invention.

FIG. 6 shows an assembled view of another stacked system including abattery and an alternate arrangement of power connections in accordancewith another embodiment of the invention.

FIG. 7 is a schematic illustration of a portion of another batterysubstrate in accordance with an embodiment of the invention.

FIG. 8 is a schematic illustration of a portion of a device including abattery, based on the battery substrate of FIG. 7, in accordance with anembodiment of the invention.

FIG. 9 is a schematic illustration of a portion of yet another batterysubstrate in accordance with an embodiment of the invention.

FIG. 10 is a schematic illustration of a portion of device including abattery, based on the battery substrate of FIG. 9, in accordance with anembodiment of the invention.

FIGS. 11A-11D show cross-sections during various steps for fabricatingan exemplary battery substrate in accordance with an embodiment of theinvention.

DETAILED DESCRIPTION

The present invention is described with reference to the attachedfigures, wherein like reference numerals are used throughout the figuresto designate similar or equivalent elements. The figures are not drawnto scale and they are provided merely to illustrate the instantinvention. Several aspects of the invention are described below withreference to example applications for illustration. It should beunderstood that numerous specific details, relationships, and methodsare set forth to provide a full understanding of the invention. Onehaving ordinary skill in the relevant art, however, will readilyrecognize that the invention can be practiced without one or more of thespecific details or with other methods. In other instances, well-knownstructures or operations are not shown in detail to avoid obscuring theinvention. The present invention is not limited by the illustratedordering of acts or events, as some acts may occur in different ordersand/or concurrently with other acts or events. Furthermore, not allillustrated acts or events are required to implement a methodology inaccordance with the present invention.

As described above, one of the inherent limitations for formingbatteries for MEMS and similar devices formed on insulating and/orsemiconducting substrates is that some of the materials in thesebatteries cannot be subsequently subjected to the high temperaturesneeded for forming additional battery layers. For example, the metalliclithium materials, commonly used as an anode in lithium battery cells,generally cannot be subjected to the anneal temperatures needed forforming the lithium cobalt oxide cathode. Accordingly, an integratedbattery comprising a stack of electrode layers is generally not possiblefor MEMS or other similar devices. As defined herein, the term“integrated battery” refers to a battery in which all electricalinterconnections between cells are made internal to the batterypackaging, as opposed to a battery that is assembled by making externalinterconnections between separately packaged individual cells. As aresult, integrated batteries for MEMS generally require the formation ofa large number of laterally spaced battery cells to provide the highvoltages necessary for MEMS. Furthermore, such a configuration alsorequires the formation of wiring structures to interconnect thelaterally spaced batteries. These additional wiring structures can alsorequire additional space on a substrate, thus further increasing thesurface area needed for the batteries. Consequently, the formation ofcompact, high voltage integrated batteries is typically difficult toachieve for MEMS devices.

To overcome the limitations of conventional devices, embodiments of theinvention provide devices including compact dual substrate batteries andmethods for forming the same. In the various embodiments of theinvention, a device including such compact batteries is formed byproviding a first substrate having a first battery bank formed thereonand a second substrate having a second battery bank disposed thereon.Each of the battery banks comprises one or more battery cells. In thevarious embodiments of the invention, the substrates are positioned tobring the first battery bank in physical and electrical contact with thesecond battery bank. This results in a series arrangement of the batterycells, with reduced space and wiring. This is conceptually illustratedwith respect to FIGS. 1-3.

Although the various embodiments of the invention will be describedprimarily with respect to lithium battery technologies and chemistries,the invention is not limited in this regard. Rather the systems andmethods described herein are equally applicable to any other batterytechnologies and chemistries. For example, the various embodiments ofthe invention can be used with other chemistries, such as zinc carbon,zinc chloride, alkaline, oxy nickel hydroxide, mercury oxide, zinc-air,silver oxide (silver-zinc), nickel cadmium, nickel-metal hydride, andlithium ion chemistries, to name a few. In the case of batterytechnologies using liquid or migrating solid or gelled electrolytematerials, the battery cells can require retention structures oralternative processes to retain the electrolyte material in place duringfabrication.

FIG. 1 is a schematic illustration of a portion of a battery substrate100, including a battery bank 102 in accordance with an embodiment ofthe invention. As shown in FIG. 1, battery bank 102 comprises a seriesof battery cells 104 disposed on the substrate 100. The battery cells104 each consist of a plurality of battery cell layers. In particular,the battery cell layers include a cathode current collector layerportion 106 disposed on substrate 100, a cathode layer portion 108disposed on portion 106, an electrolyte/separator layer portion 110disposed on portion 108, and an anode layer portion 112 disposed onportion 110. For example, in the case of a lithium battery cell,portions 106, 108, 110, and 112 can comprise a copper comprisingportion, a lithium cobalt oxide portion, a lithium phosphorousoxynitride (LiPON), and a metallic lithium portion, respectively. Theportions 106-112 are disposed on the surface of substrate 100 inlaterally spaced areas 101 of substrate 100. The term “laterallyspaced”, as used herein with respect to the placement of objects ordifferent locations, refers to objects or locations that are disposedadjacent to each other on a common surface. However, the term “laterallyspaced” also refers to adjacent areas on different surfaces that thatare partially overlapping, as described below.

In the various embodiments of the invention, the portions 106-112 of thebattery cells 104 are also arranged to have contact features that extendlaterally. That is, the battery cells 104 include first and secondadjacent surface regions along substrate 100 for contacting anode layerportion 112 and cathode layer portion 108. For example, as shown in FIG.1, the current collector layer portion 106 (electrically contactingcathode layer portion 108) can extend further along substrate 100 ascompared to portions 108-112. This extending portion defines a cathodecontact region 114 for each battery cell 104. An anode contact region116 can be defined by the top or uppermost portion of each anode layerportion 112. In the various embodiments of the invention, the cathodecontact regions 114 and the anode contact regions 116 are alternativelyarranged in series in each bank 102. That is, the batteries 104 in eachbank 102 are configured such that only one cathode contact region 114 isdefined between two anode contact regions 116. As a result, analternating series of cathode contact regions and anode contact regionsis provided across the substrate 100.

Additionally, in the various embodiments of the invention, the batterycells 104 are electrically disconnected or isolated on substrate 100.That is, electrical connections are not generally provided between twocells in the same bank. Accordingly, the upper surface of substrate 100can comprise an electrically insulating material to provide isolationbetween adjacent battery cells 104 in battery bank 102. For example, inone embodiment, the electrically insulating material can comprise asilicon oxide (Si_(x)O_(1-x)) comprising material disposed on a siliconcomprising substrate. However, the various embodiments of the inventionare not limited in this regard. Rather, any type of electricallyinsulating material can be used. Alternatively, a bottom surface ofcurrent collector layer portion 106 can comprise an electricallyinsulating material.

As shown in FIG. 1, the battery cells 104 are physically separated onthe substrate 104. In the various embodiments of the invention, thelateral spacing between battery cells 104 is selected to allow a secondbank of battery cells, disposed on a second substrate, to contact thecathode contact regions 114 and anode contact regions 116 toelectrically connect the battery cells 104 in series with the batterycells on the second substrate. Such a configuration is described withrespect to FIGS. 2A and 2B.

FIGS. 2A and B are exploded and assembled views of a portion of abattery 200 in accordance with an embodiment of the invention. As shownin FIGS. 2A and 2B, the battery 200 includes a first battery substrate202 having a first battery bank 204 of battery cells 206 disposedthereon and a second battery substrate 208 having a second battery bank210 of battery cells 212 disposed thereon. The configuration of firstbattery substrate 202 and first battery bank 204 is similar to theconfiguration shown in FIG. 1. Accordingly, the description above issufficient for describing first battery substrate 202 and first batterybank 204. Similarly, the configuration of second battery substrate 208and second battery bank 210 is similar to the configuration shown inFIG. 1. Accordingly, the description above is sufficient for describingsecond battery substrate 208 and second battery bank 210.

To assemble battery 200, battery substrate 202 and 208 are positionedsuch that their upper surfaces 202 a and 208 a, respectively, havingbattery cells 206 and 212 formed thereon, respectively, are facing eachother. As a result, battery cells 212 are inverted with respect tobattery cells 204. In addition, battery substrate 202 and 208 are placedin proximity to each other so that battery cells 206 physically andelectrically contact battery cells 212. In particular, substrates 202and 208 are positioned such that an anode contact region 206 a of abattery cell 206 electrically and physically contacts a cathode contactregion 212 b of a battery cell 212. Further, an anode contact region 212a of a battery cell 212 electrically and physically contacts a cathodecontact region 206 b of a battery cell 206. Accordingly, the series ofanode/cathode contacts results in a plurality of series-connectedbattery cells.

In the embodiment shown in FIGS. 2A and 2B, the substrates 202 and 208are approximately parallel. However, the various embodiments of theinvention are not limited in this regard. In some embodiments of theinvention, depending on the thickness of the various layers of eachbattery cell along each battery bank, a substantially non-parallelarrangement can occur.

As described above, the lateral battery cell spacing in each of batterybanks 204 and 210 allows the battery cells 206 and 212 to come intophysical and electrical contact. In particular, the lateral cell spacingin battery banks 204 and 210 is selected to allow at least a portion ofan anode contact region 212 a of one battery cell 206 to be insertedbetween two adjacent battery cells 212 in battery bank 210. Furthermore,the combined height of the anode, cathode, and electrolyte portions inbattery cells 206 and 212 are selected to allow the anode contact region206 a of a battery cell 206 to contact the cathode contact region 212 bof a first one of adjacent battery cells 212 and to allow the cathodecontact region 206 b of a battery cell 206 to contact an anode contactregion 212 a of a second of adjacent battery cells 212.

Similarly, the lateral cell spacing in battery banks 204 and 210 is alsoselected to allow at least a portion of an anode contact region 212 a ofone of battery cells 212 to be inserted between two adjacent batterycells 206 in battery bank 210. Furthermore, the combined height of theanode, cathode, and electrolyte portions in battery cells 206 and 212are selected to allow the anode contact region 212 a of battery cell 212to contact the cathode contact region 206 b of a first of adjacentbattery cells 206 and to allow the cathode contact 212 b region ofbattery cell 212 to contact an anode contact region 206 a of a second ofadjacent battery cells 206.

Although FIG. 2B shows that an anode contact region 206 a of batterycell 206 contacts relatively small portion of a cathode contact region212 a of one of battery cells 212, the invention is not limited in thisregard. In the various embodiments of the invention, the amount ofcontact between an anode contact region and a cathode contact region canvary. For example, if the materials comprising the anode contact regionand the cathode contact region provide a relatively high contactresistance, the size of the cathode contact region can be increased toreduce contact resistance. In other embodiments, the size of the cathodecontact region can be adjusted based on manufacturing tolerances ordesign constraints.

As described above, the various embodiments of the invention can be usedto provide compact integrated batteries for integrated systems, such asMEMS systems. Accordingly, a battery in accordance with an embodiment ofthe invention can be used to provide an integrated system on a singlesubstrate. This is described below with respect to FIGS. 3A and 3B.

FIGS. 3A and 3B are exploded and assembled views of a system 300including a battery 302 (unassembled in FIG. 3A) in accordance with anembodiment of the invention. As shown in FIGS. 3A and 3B, devices andother circuitry 304 can be formed on a system substrate 306 in one ormore device regions 308. Additionally, a first battery bank 310 can beformed in a battery region 312 of the system substrate 306. Theconfiguration of first battery bank 310 is similar to the configurationshown in FIG. 1. Accordingly, the description above is sufficient fordescribing first battery bank 310.

In system 300, battery 302 is formed by providing a second battery bank314 of battery cells on a second substrate 316. The configuration ofbattery bank 314 on substrate 316 is similar to the configuration shownin FIG. 1. Accordingly, the description above is sufficient fordescribing battery bank 314. The second battery bank 314 is then placedin electrical and physical contact with battery bank 312, as shown inFIG. 3B. The resulting battery 310 is similar to the battery describedabove with respect to FIG. 2B, where inverted battery cells of batterybank 314 are in physical and electrical contact with the battery cellsof battery bank 310. Thus, a alternating series arrangement of batterycells from battery banks 310 and 314 is provided, similar to the batteryin FIG. 2B. Accordingly the arrangement and operation described in FIG.2B is sufficient for describing the configuration and operation ofbattery 302.

Once assembled, battery 302 can be used in system 300 to provideelectrical power to devices 304. In the embodiment shown in FIGS. 3A and3B, the battery 302 is electrically connected to devices 304 via powerconnections 318 and 320. The power connections 318 and 320 can be usedto electrically contact the endmost battery cells in battery 302 todevices 304. The term “endmost”, as used herein with respect to batterycells, refers to the first and last battery cells of a series of batterycells in a battery. For example, in the case of system 300, theconnected battery banks 310 and 314 provide a series arrangement ofbattery cells having a first endmost battery cell 322 on substrate 306and a second endmost battery cell 324 on substrate 316. Powerconnections 318 and 320 can be configured in a variety of ways,depending on the configuration of the endmost battery cells.

In a first configuration for a power connection, an endmost battery cellcan on a substrate different from the system substrate and having ananode contact region that is not connected to other battery cells in thebattery. Such a configuration is shown in FIGS. 3A and 3B by endmostbattery cell 324. As shown in FIGS. 3A and 3B, endmost battery cell 324is inverted with a cathode contact region 324 b contacting a nextbattery cell 325 in battery 302. However, the anode contact region 324 aof endmost battery cell 324 is not in contact with any other batterycell. Instead, as shown in FIGS. 3A and 3B, power connection 318 isconfigured to extend from one of devices 304 to an area beneath theanode contact region 324 a of endmost battery cell 324. Thus, whensubstrate 316 is brought into proximity with substrate 306, the anodecontact region 324 a of endmost battery cell 324 physically andelectrically contacts power connection 318. In such embodiments, thepower connections 318 can be configured in a variety of ways. Forexample, power connection 318 can have a first portion extending fromdevices 304 and terminating in in contact pad portion beneath anodecontact region 324 a to facilitate contacting of the anode contactregion 324 a of endmost battery cell 324. However, the variousembodiments of the invention are not limited in this regard.

In a second configuration for a power connection, an endmost batterycell can be on the system substrate and having a cathode contact regionthat is not connected to other battery cells in the battery. Such aconfiguration is shown in FIGS. 3A and 3B by endmost battery cell 322.As shown in FIGS. 3A and 3B, an anode contact region 322 a of endmostbattery cell 322 is in contact with a previous battery cell 323 inbattery 302. However, the cathode contact region 322 b of endmostbattery cell 322 is not in contact with any other battery cell. Instead,as shown in FIGS. 3A and 3B, power connection 320 is configured toextend from one of devices 304 and contact the cathode contact region322 b of endmost battery cell 322. In such embodiments, power connection320 can be configured in a variety of ways. For example, powerconnection and the cathode current collector portion of endmost batterycell 322 can be integrally formed. In another example, power connection320 can at least partially overlap the cathode current collector portionof endmost battery cell 322. However, the various embodiments of theinvention are not limited in this regard.

In other configurations for power connections, additional connectionfeatures may be needed to contact the endmost battery cells in someembodiments of the invention. This is illustrated in FIG. 4. FIG. 4shows an assembled view of a system 400 including battery 402 and analternate configuration of power connections in accordance with anembodiment of the invention. The configuration of the system 400 shownin FIG. 4 is similar to that shown in FIGS. 3A and 3B. In particular,FIG. 4 includes components, the same or similar to components 302-320described above with respect to FIGS. 3A and 3B. However, in the case ofsystem 400, a battery 402, including connected battery banks 410 and 414is provided. The battery banks 410 and 414 provide a series arrangementof battery cells having a first endmost battery cell 427 on substrate316 and a second endmost battery cell 429 on substrate 306.

Therefore, in a third configuration for a power connection, an endmostbattery cell can be on a substrate different from the system substrateand having a cathode contact region that is not connected to otherbattery cells in the battery. Such a configuration is shown in FIG. 4 byendmost battery cell 427. As shown in FIG. 4, endmost battery cell 427is inverted with an anode contact region 427 a contacting a previousbattery cell 428 in battery 402. However, the cathode contact region 427b of endmost battery cell 427 is not in contact with any other batterycell. Further, if power connection 320 is extended laterally to contactendmost battery cell 427, only the anode contact region 427 a of thisbattery cell would be contacted. As a result, the power, current, andvoltage provided by endmost battery cell 427 would not be available forbattery 402. Accordingly, to contact battery cells in such aconfiguration, a power terminal 426 is configured to extend verticallyfrom power connection 320. Additionally power connection 320 and powerterminal 426 are configured to have a combined height equal to theheight of battery cells in battery bank 310. Thus, when substrate 316 isbrought into proximity with substrate 306, the cathode contact region ofendmost battery cell 427 physically and electrically contacts powerterminal 426. In such embodiments, the power terminal 426 can beprovided in a variety of ways. For example, in some embodiments of theinvention, power terminal 426 can be provided by applying a conductiveadhesive, such as a conductive epoxy or solder material to powerconnection 320. Afterwards, substrate 316 can be positioned on substrate306. In another example, power terminal 426 and power connection 320 canbe formed using the same fabrication steps used to form devices 304and/or battery bank 410. However, the various embodiments of theinvention are not limited in this regard.

In a fourth configuration for a power connection, an endmost batterycell can be on the system substrate, but having an anode contact regionthat is not connected to other battery cells in the battery. Such aconfiguration is shown in FIG. 4 by endmost battery cell 429. As shownin FIG. 4, endmost battery cell 429 has a cathode contact region 429 bcontacting an next battery cell 430 in battery 402. However, the anodecontact region 429 a of endmost battery cell 429 is not in contact withany other battery cell. Further, if power connection 318 is extendedlaterally to contact endmost battery cell 429, only the cathode contactregion 429 b of this battery cell would be contacted. As a result, thepower, current, and voltage provided by endmost battery cell 429 wouldnot be available. Alternatively, if power connection 318 is extendedlaterally and vertically over endmost battery cell 429, additionalelectrical insulating material would be needed to prevent powerconnection 318 from shorting the anode and cathode of endmost batterycell 429. This introduces additional complexity into the design andfabrication of battery cell 402 that is undesirable.

Accordingly, battery cells in such a configuration can be contacted byproviding a contact pad 432 on substrate 316 and a contact terminal 434extending vertically between power connection 318 and contact pad 432.Additionally, contact pad 432 and power terminal 434 are configured tohave a combined height equal to the height of battery cells in batterybank 414. Further, contact pad 432 is configured to have a height equalto the thickness of the cathode current collector portion of the batterycells in battery bank 414. Thus, when substrate 316 is brought intoproximity with substrate 306, the anode contact region of endmostbattery cell 429 physically and electrically contacts contact pad 432and power terminal 434 contacts power connection 318. In suchembodiments, the power terminal 434 can be provided in a variety ofways. For example, in some embodiments of the invention, power terminal434 can be provided by applying a conductive adhesive, such as aconductive epoxy or solder material to power connection 318 or contactpad 432. Afterwards, substrate 316 can be positioned on substrate 306.In another example, power terminal 434 and contact pad 432 can be formedusing the same fabrication steps used to form battery bank 414. In yetanother example, power terminal 434 and power connection 318 can beformed using the same fabrication steps used to form devices 304 and/orbattery bank 414. However, the various embodiments of the invention arenot limited in this regard.

The various embodiments of the invention are not limited to solely theconnection configurations illustrated in FIGS. 3B and 4. In the variousembodiments of the invention, any combination of connection typesdescribed above can be used in a single system, depending on theconfiguration of the battery cells in the battery banks.

In the various embodiments illustrated above in FIGS. 3A, 3B, and 4, thedevices are positioned laterally with respect to a battery in accordancewith the invention. That is, devices are formed on a same surface as thebattery cells. However, the invention is not limited in this regard andother configurations are possible. For example, alternativeconfigurations are shown in FIGS. 5 and 6.

FIG. 5 shows an assembled view of a stacked system 500 including abattery 302 in accordance with an embodiment of the invention. Theconfiguration of the system 500 shown in FIG. 5 is similar to that shownin FIGS. 3A and 3B. FIG. 6 shows an assembled view of another stackedsystem 600 including a battery 402 and an alternate arrangement of powerconnections in accordance with another embodiment of the invention. Theconfiguration of the system 600 shown in FIG. 6 is similar to that shownin FIG. 4. However, in the case of systems 500 and 600, the devices 504,respectively, are not positioned on the same surface of the systemsubstrate on which a respective battery is formed. Rather the devices504 are formed on an opposing surface of system substrate 306 in systems500 and 600. Such a configuration provides a stacked structure of abattery and devices. As a result, the size of systems 500 and 600 can bereduced as compared to systems 300 and 400, respectively.

In systems 500 and 600, electrical connections to batteries 302 and 402,respectively, can be provided in a variety of ways. First, batteries 302and 402 can be connected to power connections 318 and 320, as describedabove with respect to FIGS. 3A, 3B, and 4. For example, in someembodiments, the configuration of FIG. 5 for connecting endmost batterycells 322 and 324 of battery 302 to power connections 320 and 318,respectively, can be used. In other embodiments, the configuration ofFIG. 6 for connecting endmost battery cells 323 and 325 to powerconnections 320 and 318, respectively, can also be used. Additionallyany combination of these connections can also be used, depending on theconfiguration of the battery banks provided.

Next connection of power connections 318 and 320 to devices 504 can beaccomplished in several ways. In a first configuration, connections canbe made through system substrate 306. For example, electricallyconductive elements can be formed in substrate 306 using thru substratevias 536 and 538, as shown in FIGS. 5 and 6. In such a configuration, anopening or via can be formed in substrate 306 between its upper andlower surfaces. The opening or via can then be at least partially filledwith an electrically conductive material to provide an electricallyconductive connection. In a second configuration, connections can bemade around substrate 306. In such configurations, power connections 318and 320 can extend around substrate 306 and electrically contact devices304. This is shown in FIGS. 5 and 6 by the extension portions 518 and520 of power connections 318 and 320, respectively. However, the variousembodiments of the invention are not limited to solely one connectiontype between battery 302 and devices 304. In the various embodiments ofthe invention, any combination of connection types described above canbe used in a single system.

In the various embodiments described above, the battery cells includelayers that extend parallel to the substrate they are formed upon.However, such a configuration ultimately limits the current and voltagethat can be supplied, since such parameters are ultimately defined bythe surface area of the various layers or portions of each battery cell.In view of this limitation, another aspect of the invention provides thelayers in the battery cells to extend at least partially in a verticaldirection. As a result, the total surface area of the layers of eachbattery cell can be increased without needing to increase the totalamount of area needed on a substrate. This is conceptually illustratedin FIGS. 7-10.

FIG. 7 is a schematic illustration of a portion of a battery substrate700 in accordance with an embodiment of the invention. Like the batterysubstrate in FIG. 1, the battery substrate 700 includes a battery bankincluding at least one battery cell 702 having a cathode currentcollector layer portion 706 disposed on substrate 700, a cathode layerportion 708 disposed on portion 706, an electrolyte/separator layerportion 710 disposed on portion 708, and an anode layer portion 712disposed on portion 710.

Like the battery cells in FIG. 1, the portions 706-712 of the batterycell 702 are also arranged to have contact features that extendlaterally. That is, the battery cells 702 include first and secondadjacent surface regions extending along substrate 700 for contactinganode layer portion 712 and cathode layer portion 708. For example, asshown in FIG. 7, the current collector layer portion 706 (electricallycontacting cathode layer portion 708) can extend further laterally ascompared to portions 708-712 to define a cathode contact region 714 forbattery cell 702. An anode contact region 716 can be defined by the topor uppermost portion of anode layer portion 712. In the variousembodiments of the invention, the cathode contact regions 714 and theanode contact regions 716 are alternatively arranged in series, asdescribed above in FIG. 1. That is, the battery cells on substrate 700are configured such that only one cathode contact region 714 is definedbetween two anode contact regions 716 in a battery bank. As a result, analternating series of cathode contact regions and anode contact regionsis provided across the substrate 700 in a battery bank.

Unlike the battery cells in FIG. 1, the battery cell in FIG. 7 alsoextends vertically and laterally. In the embodiment illustrated in FIG.7, this is achieved by forming layer 706 to include at least one portionof a greater thickness than the extending portion defining cathodecontact region 714. Thus, after layers 708-712 are formed, a batterycell with an effective larger area is formed, but over the same area ofsubstrate 700. Such a larger area battery cell can therefore provide alarger capacity cell with increased current draw capabilities than abattery cell extending solely in lateral directions, such as the batterycells in FIGS. 1-6. Accordingly, as compared to conventional integratedbatteries, an integrated battery with substantially the same footprintas a conventional integrated battery can be fabricated that providessubstantially higher voltage, capacity, and current draw capabilities.Such a battery is shown in FIG. 8.

FIG. 8 is a schematic illustration of a portion of a battery 800, basedon the battery substrate of FIG. 7, in accordance with an embodiment ofthe invention. As shown in FIG. 8, the battery 800 includes a firstbattery substrate 802 having a first battery bank 804 of battery cells806 disposed thereon and a second battery substrate 808 having a secondbattery bank 810 of battery cells 812 disposed thereon. Theconfiguration of the battery cells in first battery substrate 802 andfirst battery bank 804 is similar to the configuration shown in FIGS. 1and 7. Accordingly, the description above is sufficient for describingfirst battery substrate 802 and first battery bank 804. Similarly, theconfiguration of second battery substrate 808 and second battery bank810 is similar to the configuration shown in FIGS. 1 and 7. Accordingly,the description above is sufficient for describing second batterysubstrate 808 and second battery bank 810.

To assemble battery 800, battery substrate 802 and 808 are positionedsuch that their upper surfaces 802 a and 808 a are opposing (i.e. facingeach other). That is, upper surface 802 a, having battery cells 806formed thereon, and upper surface 808 a, having battery cells 812 formedtherein, are arranged to face each other. As a result, battery cells 812are inverted with respect to battery cells 806. In addition, batterysubstrate 802 and 808 are placed in proximity to each other so thatbattery cells 806 physically and electrically contact battery cells 812.In particular, substrates 802 and 808 are positioned such that an anodecontact region 806 a of a battery cell 806 electrically and physicallycontacts a cathode contact region 812 b of a battery cell 812 and suchthat an anode contact region 812 a of a battery cell 812 electricallyand physically contacts a cathode contact region 806 b of a battery cell806. Accordingly, the collection of anode/cathode contacts results in aplurality of series-connected battery cells, similar to theconfiguration shown in FIGS. 1-6.

Although the embodiment in FIGS. 7 and 8 shows a triangularcross-section for the thicker portion of the cathode current collectorlayer, the various embodiments of the invention are not limited in thisregard. In the various embodiments of the invention, the cross-sectionshape of the cathode current collector layer can be configured to haveany other shape. For example, the cross-section shape can berectangular, elliptical, or trapezoidal. However, the invention is notlimited in this regard.

In some cases direct contact of the anode contact region and the cathodecontact region can result in alloying of the metals comprising the anodelayer and the cathode current collector layer. If the anode contactregion and the cathode contact region are in contact over a relativelylarge area, the alloying will not generally adversely affect theelectrical contact between the two regions. However, in the case of thebattery of FIG. 8, the anode contact region is contacting the cathodecontact region over a relatively small area. Accordingly, even if arelatively small amount of alloying occurs, the variation in theproperties of the electrical contact can vary significantly. This canincrease, for example, the contact resistance between the layers,resulting in reduced current and voltage being delivered by the battery.Therefore, in some embodiments of the invention, a barrier metal contactpad can be provided. This is shown in FIGS. 7 and 8. In particular, asshown in FIG. 7, battery cell 702 can further include a barrier contactpad 726 formed on cathode contact region 714. Therefore, when suchbattery cells are used in substrates 802 and 808 in FIG. 8, little or noalloying at the anode contact regions 806 a and 812 b occurs.

Although the embodiments in FIGS. 7 and 8 illustrate providing a thickercathode current layer portion to cause the battery cell layers to extendvertically, the various embodiments of the invention are not limited inthis regard. For example, in some embodiments of the invention, thesubstrate can be configured to include features, such as projections orrecesses, to cause the layers in each of the battery cells to at leastpartially extend vertically. In the case of projections, theconfiguration of the resulting battery is substantially similar to thatshown in FIGS. 7 and 8 with the exception that substrate 700 wouldprovide projections, as indicated by the dotted line 718 in FIG. 7,instead of the thicker cathode current collector layer portions. Thecase of a recess is shown below in FIGS. 9 and 10.

FIG. 9 is a schematic illustration of a portion of yet another batterysubstrate 900 in accordance with an embodiment of the invention. Likethe battery substrate in FIG. 1, the battery substrate 900 includes abattery bank including at least one battery cell 902 having a cathodecurrent collector layer portion 906 disposed on substrate 900, a cathodelayer portion 908 disposed on portion 906, an electrolyte/separatorlayer portion 910 disposed on portion 908, and an anode layer portion912 disposed on portion 910.

Although the embodiment in FIG. 9 shows a triangular cross-section forthe recess 918, the various embodiments of the invention are not limitedin this regard. In the various embodiments of the invention, thecross-section shape of the cathode current collector layer can beconfigured to have any other shape. For example, the cross-section shapecan be rectangular, elliptical, or trapezoidal. However, the inventionis not limited in this regard.

Unlike the battery cell in FIG. 1, a recess 918 can be provided insubstrate 900 for battery cell 902. The layers 906-914 can be depositedon substrate 900 to follow the contour of recess 918. As a result,battery cell extends laterally and vertically to increase its effectivearea and therefore increase the supplied voltage and current.

Like the battery cells in FIG. 1, the battery cell 902 also includesfirst and second laterally adjacent regions for contacting anode layerportion 912 and cathode layer portion 908. For example, as shown in FIG.9, the current collector layer portion 906 (electrically contactingcathode layer portion 908) can extend further laterally in a firstdirection as compared to portions 908-912 to define a cathode contactregion 914 for battery cell 902. In particular, layer 906 can beconfigured to extend further out of recess 918 in first direction.

An anode contact region 916 can be defined by providing a portion ofanode layer 912 that extends out of recess 918 in second direction toform an uppermost portion of anode layer portion 912. In the variousembodiments of the invention, the cathode contact regions 914 and theanode contact regions 916 are alternatively arranged in series, asdescribed above in FIG. 1. That is, the battery cells on substrate 900are configured such that only one cathode contact region 914 is definedbetween two anode contact regions 916. As a result, an alternatingseries of cathode contact regions and anode contact regions is providedacross the substrate 900.

Thus, after recess 918 and layers 908-912 are formed, a battery cellwith an effective larger area is formed. Such a larger area battery cellcan therefore provide a larger capacity cell with increased current drawcapabilities than a battery cell extending solely in lateral directions,such as the battery cells in FIGS. 1-6. Accordingly, as compared toconventional integrated batteries, an integrated battery withsubstantially the same footprint as a conventional integrated batterycan be fabricated that provides substantially higher voltage, capacity,and current draw capabilities. Such a battery is shown in FIG. 10.

FIG. 10 is a schematic illustration of a portion of a battery 1000,based on the battery substrate of FIG. 9, in accordance with anembodiment of the invention. As shown in FIG. 10, the battery 1000includes a first battery substrate 1002 having a first battery bank 1004of battery cells 1006 disposed thereon and a second battery substrate1008 having a second battery bank 1010 of battery cells 1012 disposedthereon. The configuration of the battery cells in first batterysubstrate 1002 and first battery bank 1004 is similar to theconfiguration shown in FIG. 9. Accordingly, the description above issufficient for describing first battery substrate 1002 and first batterybank 1004. Similarly, the configuration of second battery substrate 1008and second battery bank 1010 is similar to the configuration shown inFIG. 9. Accordingly, the description above is sufficient for describingsecond battery substrate 1008 and second battery bank 1010.

To assemble battery 1000, battery substrate 1002 and 1008 are positionedsuch that their upper surfaces 1002 a and 1008 a, respectively, havingbattery cells 1006 and 1012, respectively, are facing each other. As aresult, battery cells 1012 are inverted with respect to battery cells1004. In addition, battery substrate 1002 and 1008 are placed inproximity to each other so that battery cells 1006 physically andelectrically contact battery cells 1012. In particular, substrates 1002and 1008 are positioned such that an anode contact region 1006 a of abattery cell 1006 electrically and physically contacts a cathode contactregion 1012 b of a battery cell 1012 and such that an anode contactregion 1012 a of a battery cell 1012 electrically and physicallycontacts a cathode contact region 1006 b of a battery cell 1006.Accordingly, the collection of anode/cathode contacts results in aplurality of series-connected battery cells, similar to theconfiguration shown in FIGS. 1-6.

The battery substrates illustrated in FIGS. 1-10 can be fabricated in avariety of ways. One exemplary method is shown below in FIGS. 11A-11D.FIGS. 11A-11D show cross-sections during various steps of fabricating anexemplary battery substrate in accordance with an embodiment of theinvention. In particular, FIGS. 11A-11D show cross-sections for formingthe battery cells in FIGS. 9 and 10. However, the various steps in themethod described below are equally applicable to fabricating batterysubstrates in accordance with the various embodiments of the invention.

The fabrication process can begin with providing substrate 900 on whichthe battery cell 902 is to be formed on. In some embodiments, thesubstrate 900 can include a semiconducting surface. For example, thesubstrate can be a monocrystalline semiconductor wafer, asemiconductor-on-insulator (SOI) wafer, a flat panel display (e.g., asilicon layer over a glass plate), or any other type of substrate usedto form an electronic device. Substrate 900 can include a dopant, suchas including an n-type or p-type dopant. Moreover, substrate 900 caninclude electronic components or portions of electronic componentspreviously formed thereon. Such electronic components can include forexample, implant regions, field isolation regions, or other layers usedto form electronic components such as transistors and MEMS devices.However, the invention is not limited in this regard and the electroniccomponents may be formed after formation of battery 902.

Once a substrate 900 is provided, vertically extending features can beformed. This is illustrated in FIG. 11A, showing recess 918 being formedin substrate 900. Recess 918 can be formed in a variety of ways. In oneembodiment, recesses can be formed by a photolithography techniqueincluding use of a reticle to expose particular portions of a resistlayer (not shown) deposited on substrate 900 to radiation followed bysubsequent removal of the exposed portions to form a patterned resistlayer having openings. A removal process can then be used to removeportions of the substrate to form recess 918. In general, the recess 918can be formed using a selective removal process. In accordance with anembodiment of the invention, the formation of recess 918 includes anetching technique, which can include an anisotropic etch or an isotropicetch using a plasma or other dry etch process. Other embodiments maymake use of a wet etch technique. A similar process can be used to formprojections.

As described above, the substrate can comprise a semiconductingsubstrate. Therefore, to provide electrical isolation between thebattery cells formed thereon, the remaining surface of substrate must besomehow converted to an electrically non-conductive surface. In oneembodiment, this can be accomplished by the growth or deposition of anelectrically insulating layer 1102 on substrate 900 and in recesses 918.For example, in the case of a silicon comprising substrate, a siliconoxide comprising layer can be grown or deposited on the substrate afterrecesses are formed.

Once recess 918 (and if necessary layer 1102) is formed in substrate900, the cathode current collector layer portion 906 can be formed onsubstrate 900 for each battery cell. Cathode current collector layerportion 906 can be formed in a variety of ways. First, a layer ofmaterial comprising the cathode current collector layer portion 906 canbe deposited on substrate 900. For example, in the case of a lithiumcell, a layer of a copper comprising material can be deposited on thesubstrate. For example, a chemical vapor deposition or an electroplatingtechnique can be used. Additionally, one or more adhesion layers (notshown) can also be formed to improve adhesion between the cathodecurrent collector layer portion 906 and the underlying substrate 900.The cathode current collector layer portion 906 can then be formed foreach battery cell by a photolithography technique that defines thecathode current collector layer portion 906 in recess 918 and cathodecontact region 914 outside recess 918, as described above. A removalprocess can then be used to form the cathode current collector layerportion 906. For example, in the case of a copper comprising material,an etching technique can be used, which can include an anisotropic etchor an isotropic etch using a plasma or other dry etch process. Otherembodiments may make use of a wet etch technique. The result of thisprocess is shown in FIG. 11B

After the cathode current collector layer portion 906 is formed, thecathode layer portion 908 can be formed. Cathode layer portion 908 canbe formed in a variety of ways. First, a layer of material comprisingthe cathode layer portion 906 can be deposited on substrate 900. Forexample, in the case of a lithium cell, a layer of lithium cobalt oxidematerial can be deposited on substrate 900 over at least recess 918. Forexample, a sputtering or chemical vapor deposition technique can beused. The cathode layer portion 908 can then be formed for each batterycell by a photolithography technique that defines a pattern for formingthe cathode layer portion 908 in recess 918, as described above. Aremoval process can then be used to form the cathode layer portion 908.For example, an etching technique can be used, which can include ananisotropic etch or an isotropic etch using a plasma or other dry etchprocess. Other embodiments may make use of a wet etch technique.Additionally, before or after photolithography and etching, an annealstep is used to cure the lithium cobalt oxide. The result of thisprocess is shown in FIG. 11C

Once the cathode layer portion 908 is formed, the electrolyte/separatorlayer portion 910 can be formed. Electrolyte/separator layer portion 910can be formed in a variety of ways. First, a layer of materialcomprising the electrolyte/separator layer portion 910 can be depositedon substrate 900. For example, an electrolyte layer can comprise one ormore layers of a solid-state ion conductor or a gelled electrolyte. Forexample, in the case of a lithium cell, a layer of LiPON material thatconducts lithium ions but is electrically insulating can be deposited onsubstrate 900 over at least recess 918. In some embodiments of theinvention, such a LiPON materials can be deposited by magnetronsputtering in a nitrogen plasma. However, the various embodiments of theinvention are not limited in this regard and any other methods fordepositiing LiPON can be used. The electrolyte/separator layer portion910 can then be formed for each battery cell by a photolithographytechnique that defines a pattern for forming the electrolyte/separatorlayer portion 910 in recess 918, as described above. A removal processcan then be used to form the electrolyte/separator layer portion 910.For example, an etching technique can be used, which can include ananisotropic etch or an isotropic etch using a plasma or other dry etchprocess. Other embodiments may make use of a wet etch technique. Theresult of this process is shown in FIG. 11D

Once the electrolyte/separator layer portion 910 is formed, the anodelayer portion 912 can be formed. Anode layer portion 912 can be formedin a variety of ways. First, a layer of material comprising the anodelayer portion 912 can be deposited on substrate 900. For example, in thecase of a lithium cell, a layer of lithium metal material can bedeposited on substrate 900. The anode layer portion 912 can then beformed for each battery cell by a photolithography technique thatdefines a pattern for forming the anode layer portion 912 in recess 918and anode contact region 916 extending out of recess 918, as describedabove. A removal process can then be used to form the anode layerportion 912 and anode contact region 916. For example, an etchingtechnique can be used, which can include an anisotropic etch or anisotropic etch using a plasma or other dry etch process. Otherembodiments may make use of a wet etch technique. The result of thisprocess is shown in FIG. 11E.

While various embodiments of the present invention have been describedabove, it should be understood that they have been presented by way ofexample only, and not limitation. Numerous changes to the disclosedembodiments can be made in accordance with the disclosure herein withoutdeparting from the spirit or scope of the invention. Thus, the breadthand scope of the present invention should not be limited by any of theabove described embodiments. Rather, the scope of the invention shouldbe defined in accordance with the following claims and theirequivalents.

Although the invention has been illustrated and described with respectto one or more implementations, equivalent alterations and modificationswill occur to others skilled in the art upon the reading andunderstanding of this specification and the annexed drawings. Inaddition, while a particular feature of the invention may have beendisclosed with respect to only one of several implementations, suchfeature may be combined with one or more other features of the otherimplementations as may be desired and advantageous for any given orparticular application.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. Furthermore, to the extent that the terms “including”,“includes”, “having”, “has”, “with”, or variants thereof are used ineither the detailed description and/or the claims, such terms areintended to be inclusive in a manner similar to the term “comprising.”

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andwill not be interpreted in an idealized or overly formal sense unlessexpressly so defined herein.

1. An electronic system, comprising: a first substrate having a firstsurface and a second substrate having a second surface opposed from saidfirst surface; and a plurality of battery cell layers disposed onlaterally spaced areas of said first and second surfaces; whereinportions of said battery cell layers on said first surface are inphysical contact with portions of said battery cell layers on saidsecond surface, and wherein said battery cell layers on said firstsurface and said second surface form a plurality of electricallyinterconnected battery cells on said first and said second surfaces thatare laterally spaced apart and define one or more batteries.
 2. Theelectronic system according to claim 1, wherein said battery cell layersdisposed on said plurality of laterally spaced areas on said firstsurface form a first plurality of laterally spaced battery cells.
 3. Theelectronic system according to claim 2, wherein said battery cell layersdisposed on said plurality of laterally spaced areas on said secondsurface form a second plurality of laterally spaced battery cells. 4.The electronic system according to claim 3, wherein said physicalcontact provides an electrical connection between an anode of a firstbattery cell on said first surface and a cathode of a second batterycell on said second surface.
 5. The electronic system according to claim4, wherein said first plurality of laterally spaced battery cells form afirst periodic pattern that is spatially offset from a second periodicpattern of said second plurality of laterally spaced battery cells. 6.The electronic system according to claim 5, wherein said first andsecond periodic patterns are selected so that each of said firstplurality of laterally spaced battery cells are aligned to overlap twoadjacent ones of said laterally spaced battery cells on said secondsurface.
 7. The electronic system according to claim 1, wherein saidlaterally spaced areas on said first surface form a periodic patternthat is spatially offset from a second periodic pattern of saidlaterally spaced areas on said second surface.
 8. The electronic systemaccording to claim 7, wherein each of said laterally spaced areas onsaid first surface are aligned to overlap two laterally spaced areas onsaid second surface.
 9. The electronic system according to claim 1,wherein said physical contact provides an electrical connection betweenan anode of a first of said interconnected battery cells on said firstsurface and a cathode of a second of said interconnected battery cellson said second surface.
 10. The electronic system according to claim 1,wherein at least one layer of said battery cell layers on said firstsurface is overlapped with at least one layer of said battery celllayers on said second surface to form said physical contact.
 11. Theelectronic system according to claim 1, further comprising at least onedevice disposed on one of said first and said substrates and powered byat least one of said batteries.
 12. The electronic system according toclaim 1, wherein at least one of said battery cell layers has a surfacethat extends at least in one direction transverse to said first andsecond surfaces.
 13. The electronic system according to claim 1, whereinat least one of said battery cell layers has a surface that extends inat least in one direction parallel to said first and second surfaces.14. The electronic system according to claim 1, wherein said laterallyspaced areas comprise at least one recessed surface feature formed in atleast one of said first and second surfaces.
 15. The electronic systemaccording to claim 1, wherein said laterally spaced areas comprise atleast one raised surface feature projecting from at least one of saidfirst and second surfaces.
 16. A method for forming an electronicsystem, comprising: providing a first substrate having a first surfaceand a second substrate having a second surface; disposing a plurality ofbattery cell layers on respective plurality of laterally spaced areas onsaid first and second surfaces; and aligning said first and said secondsubstrates so that portions of said battery cell layers on said firstsurface are in physical contact with portions of said battery celllayers on said second surface and said battery cell layers on said firstsurface and said second surface form a plurality of electricallyinterconnected battery cells on said first and said second surfaces thatare laterally spaced apart and define one or more batteries.
 17. Themethod of claim 16, wherein said disposing further comprises formingsaid battery cell layers on said plurality of laterally spaced areas onsaid first surface to form a first plurality of laterally spaced batterycells.
 18. The method of claim 17, wherein said disposing furthercomprises forming said battery cell layers on said plurality oflaterally spaced areas on said second surface to form a second pluralityof laterally spaced battery cells.
 19. The method of claim 18, whereinsaid aligning further comprises arranging said physical contact toprovide an electrical connection between an anode of a first batterycell on said first surface and a cathode of a second battery cell onsaid second surface.
 20. The method of claim 19, wherein said disposingfurther comprises arranging said first plurality of laterally spacedbattery cells to form a first periodic pattern that is spatially offsetfrom a second periodic pattern of said second plurality of laterallyspaced battery cells.
 21. The method of claim 20, wherein said disposingfurther comprises selecting said first and second periodic patterns sothat each of said first plurality of laterally spaced battery cells arealigned to overlap two adjacent ones of said laterally spaced batterycells on said second surface.
 22. The method of claim 16, wherein saiddisposing further comprises selecting said laterally spaced areas onsaid first surface to form a periodic pattern that is spatially offsetfrom a second periodic pattern of said laterally spaced areas on saidsecond surface.
 23. The method of claim 22, wherein said aligningfurther comprises arranging each of said laterally spaced areas on saidfirst surface to overlap two laterally spaced areas on said secondsurface.
 24. The method of claim 16, wherein aligning further comprisesarranging said physical contact to provide an electrical connectionbetween an anode of a first of said interconnected battery cells on saidfirst surface and a cathode of a second of said interconnected batterycells on said second surface.
 25. The method of claim 16, whereinaligning further comprises arranging at least one layer of said batterycell layers on said first surface to overlap at least one layer of saidbattery cell layers on said second surface to form said physicalcontact.
 26. The method of claim 16, further comprising forming at leastone device on one of said first and said substrates and powered by atleast one of said batteries.
 27. The method of claim 16, wherein saiddisposing further comprises forming at least one of said battery celllayers to have a surface that extends at least in one directiontransverse to said first and second surfaces.
 28. The method of claim16, wherein said disposing further comprises forming at least one ofsaid battery cell layers to have a surface that extends in at least inone direction parallel to said first and second surfaces.
 29. The methodof claim 16, wherein said providing further comprises forming saidlaterally spaced areas to comprise at least one recessed surface featureformed in at least one of said first and second surfaces.
 30. The methodof claim 16, wherein said providing further comprises forming saidlaterally spaced areas to comprise at least one raised surface featureprojecting from at least one of said first and second surfaces.